Exactly Dr Perkins!! The oil gets pre warmed up to about 250f-300f for 3 reasons. First, this is above the boiling point of water. Sometimes, depending on how careful the restaurants are, there can be a little bit of water and cleaning solution left in the oil cubie. It is very obvious if there is water in the oil and it cooks off quickly. Secondly, it is much easier to filter out the French fry bits and passes quickly through the restaurant style 10" cone filters without getting clogged. Finally, it is much closer to the flash point of the oil when burning in the chamber. Most veggie oils flash at 450f +- so the spray into the flame ball ignites instantly and is self sustaining. There is no smell in the exhaust if it is burning right. It can be a bit tricky to get a proper balance between the fuel and the air passing through the needle valves and all of the different veggie oils burn slightly differently so there is no standard setting. Once it is set and burning properly, I rarely have to adjust the flame and one 18L cornellious keg tank will burn for about 2.5 hours.
Ninja edit- 2.5 hours in my 2x8 flat D&G pans. It can be turned down and burn slower if I want. I have also popped the spray nozzle out of my rig and quickly set it up at my buddies. He has a small CDL 18x48 Hobby. We got the tank and burner set up there in minutes and got the flame roaring. Of course the fuel was turned down for the smaller rig. It lasted over 5 hours of continuous burn.
